The best answer is
<span>A point on the PPC indicates maximum utilization of available resources.
The PPC is a representation of the maximum outputs, usually as a tradeoff between two goods, given maximum utilization of available resources. Naturally, producing one good leaves less resources and other inputs available for another good. </span>
Not having the source material my guess is D
The answer is: B. accommodation
Accommodation refers to a new information that can change people's existing perspective and transformed it into a new one.
in the case above, Ella's existing perspective was that all birds tweet. The parrots that showed by her friends is the new information. After seeing the new information, Ella changed her perspective towards how birds should sound.
The growth of civilization most clearly traced is farming
